Module: coarse_sun_sensor

This class is designed to model the state of a single coarse sun sensor attached to a spacecraft. It emulates the “counts” that will typically be output by the ADC on board of a spacecraft.

The module PDF Description contains further information on this module’s function, how to run it, as well as testing. The corruption types are outlined in this PDF Description.

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Enums

enum CSSFaultState_t

Values:

enumerator CSSFAULT_OFF

CSS measurement is set to 0 for all future time

enumerator CSSFAULT_STUCK_CURRENT

CSS measurement is set to current value for all future time

enumerator CSSFAULT_STUCK_MAX

CSS measurement is set to maximum value for all future time

enumerator CSSFAULT_STUCK_RAND

CSS measurement is set to randomly selected value for all future time

enumerator CSSFAULT_STUCK

CSS measurement is set to percent value for all future time

enumerator CSSFAULT_RAND

CSS measurement returns uniformly distributed random values between 0 and max

enumerator MAX_CSSFAULT

class CoarseSunSensor : public SysModel

Public Functions

CoarseSunSensor()

Initialize a bunch of defaults in the constructor. Is this the right thing to do?

~CoarseSunSensor()

There is nothing to do in the default destructor.

void CrossInit()

method for initializing cross dependencies

This method simply calls the LinkMessages method to ensure that input messages are matched correctly.

void SelfInit()

method for initializing own messages

This method performs all of the internal initialization for the model itself. Primarily that involves initializing the random number generator and creates the output message

void UpdateState(uint64_t CurrentSimNanos)

method to update state for runtime

This method is called at a specified rate by the architecture. It makes the calls to compute the current sun information and write the output message for the rest of the model.

Parameters

• CurrentSimNanos: The current simulation time from the architecture

void setUnitDirectionVectorWithPerturbation(double cssThetaPerturb, double cssPhiPerturb)

utility method to perturb CSS unit vector

Set the unit direction vector (in the body frame) with applied azimuth and elevation angle perturbations.

Parameters

• [in] cssPhiPerturb: [rad] css elevation angle, measured positive toward the body z axis from the x-y plane

• [in] cssThetaPerturb: [rad] css azimuth angle, measured positive from the body +x axis around the +z axis

void setBodyToPlatformDCM(double yaw, double pitch, double roll)

utility method to configure the platform DCM

Set the direction cosine matrix body to css platform tranformation with 3-2-1 angle set.

Parameters

• yaw: (radians) third axis rotation about body +z

• pitch: (radians) second axis rotation about interim frame +y

• roll: (radians) first axis rotation about platform frame +x

void readInputMessages()

method to read the input messages

void computeSunData()

method to get the sun vector information

This method computes the sun-vector heading information in the vehicle body frame.

void computeTrueOutput()

method to compute the true sun-fraction of CSS

This method computes the tru sensed values for the sensor

void applySensorErrors()

method to set the actual output of the sensor with scaling/kelly

This method takes the true observed cosine value (directValue) and converts it over to an errored value. It applies noise to the truth.

void scaleSensorValues()

void applySaturation()

apply saturation effects to sensed output (floor and ceiling)

void writeOutputMessages(uint64_t Clock)

method to write the output message to the system

This method writes the output message. The output message contains the current output of the CSS converted over to some discrete “counts” to emulate ADC conversion of S/C.

Parameters

• Clock: The current simulation time

Public Members

std::string sunInMsgName

[-] Message name for sun data

std::string stateInMsgName

[-] Message name for spacecraft state */

std::string cssDataOutMsgName

[-] Message name for CSS output data */

std::string sunEclipseInMsgName

[-] Message name for sun eclipse state message

CSSFaultState_t faultState

[-] Specification used if state is set to COMPONENT_FAULT */

double theta

[rad] css azimuth angle, measured positive from the body +x axis around the +z axis

double phi

[rad] css elevation angle, measured positive toward the body +z axis from the x-y plane

double B2P321Angles[3]

[-] 321 Euler anhles for body to platform

Eigen::Matrix3d dcm_PB

[-] DCM from platform frame P to body frame B

Eigen::Vector3d nHat_B

[-] css unit direction vector in body frame components

Eigen::Vector3d sHat_B

[-] unit vector to sun in B

double directValue

[-] direct solar irradiance measurement

double albedoValue

[-] albedo irradiance measurement

double scaleFactor

[-] scale factor applied to sensor (common + individual multipliers)

double sensedValue

[-] total measurement including perturbations

double trueValue

[-] total measurement without perturbations

double kellyFactor

[-] Kelly curve fit for output cosine curve

double fov

[-] rad, field of view half angle

Eigen::Vector3d r_B

double senBias

[-] Sensor bias value

double senNoiseStd

[-] Sensor noise value

uint64_t outputBufferCount

[-] number of output msgs stored

double maxOutput

[-] maximum output (ceiling) for saturation application

double minOutput

[-] minimum output (floor) for saturation application

double walkBounds

[-] Gauss Markov walk bounds

double kPower

[-] Power factor for kelly curve

BSKLogger bskLogger

BSK Logging

Private Members

int64_t sunInMsgID

[-] Connect to input time message

int64_t stateInMsgID

[-] Connect to input time message

int64_t cssDataOutMsgID

[-] Connect to output CSS data

int64_t sunEclipseInMsgId

[-] Connect to input sun eclipse message

SpicePlanetStateSimMsg sunData

[-] Unused for now, but including it for future

SCPlusStatesSimMsg stateCurrent

[-] Current SSBI-relative state

EclipseSimMsg sunVisibilityFactor

[-] scaling parameter from 0 (fully obscured) to 1 (fully visible)

double sunDistanceFactor

GaussMarkov noiseModel

[-] Factor to scale cosine curve magnitude based on solar flux at location

Saturate saturateUtility

[-] Gauss Markov noise generation model

class CSSConstellation : public SysModel

#include <coarse_sun_sensor.h>

Constellation of coarse sun sensors for aggregating output information.

This class is a thin container on top of the above coarse-sun sensor class.

It is used to aggregate the output messages of the coarse sun-sensors into a a single output for use by downstream models.

Public Functions

CSSConstellation()

[-] Default constructor

The default constructor for the constellation really just clears the sensor list.

~CSSConstellation()

[-] Default Destructor

The default destructor for the constellation just clears the sensor list.

void CrossInit()

[-] Method for initializing cross dependencies

This method loops through the sensor list and calls the CrossInit method for all of those sensors.

void SelfInit()

[-] Method for initializing own messages

This method loops through the sensor list and calls the self init method for all of them.

void UpdateState(uint64_t CurrentSimNanos)

[-] Main update method for CSS constellation

void appendCSS(CoarseSunSensor newSensor)

[-] Method for adding sensor to list

Public Members

uint64_t outputBufferCount

[-] Number of messages archived in output data

std::string outputConstellationMessage

[-] Message name for the outgoing message

int64_t outputConstID

[-] output ID for the outgoing message

std::vector<CoarseSunSensor> sensorList

[-] List of coarse sun sensors in constellation

Private Members

CSSArraySensorIntMsg outputBuffer

[-] buffer used to write output message